October 27, 2010

Origin of Indian Austroasiatic speakers

Mol Biol Evol (2010) doi: 10.1093/molbev/msq288

Population Genetic Structure in Indian Austroasiatic speakers: The Role of Landscape Barriers and Sex-specific Admixture

Gyaneshwer Chaubey et al.

The geographic origin and time of dispersal of Austroasiatic (AA) speakers, presently settled in South and Southeast Asia, remains disputed. Two rival hypotheses, both assuming a demic component to the language dispersal, have been proposed. The first of these places the origin of Austroasiatic speakers in Southeast Asia with a later dispersal to South Asia during the Neolithic, whereas the second hypothesis advocates pre-Neolithic origins and dispersal of this language family from South Asia. To test the two alternative models this study combines the analysis of uniparentally inherited markers with 610,000 common SNP loci from the nuclear genome. Indian AA speakers have high frequencies of Y chromosome haplogroup O2a; our results show that this haplogroup has significantly higher diversity and coalescent time (17-28 KYA) in Southeast Asia, strongly supporting the first of the two hypotheses. Nevertheless, the results of principal component and “structure-like” analyses on autosomal loci also show that the population history of AA speakers in India is more complex, being characterised by two ancestral components - one represented in the pattern of Y chromosomal and EDAR results, the other by mtDNA diversity and genomic structure. We propose that AA speakers in India today are derived from dispersal from Southeast Asia, followed by extensive sex-specific admixture with local Indian populations.

13 comments:

BS. They didn't sample any Indo-European-speaking population from India. I am sure they would show up genetically pretty close to Dravidian-speakers of southern India, especially the ones geographically near to Dravidian-speakers.

As always, Uyghurs and Hazaras overlap in the PCA diagram and they have very very similar component distribution in the STRUCTURE-like analysis, further confirming my guess that they are basically one and the same people, as there were many, maybe more than Mongols, Central Asian Turkics (mainly from the eastern parts, including Uyghur lands) in the Mongol armies and their genetic constitution was probably very close to Uyghurs, who are Turkics from East Central Asia (now a part of China).

So, Austroasiatic would arrive in the Neolithic predominantly through men who took local women as brides. Presumably, this would coincide with the oldest use of rice in India, which current research dates to around 2300 BCE in Lothal in Gujarat. Pre-Vedic, but only by a few hundred years.

If so, it undermines Witzel's hypothesis that Austroasiatic is related linguistically to Harappan, which was present thousands of years earlier and is remote from Austro-Asiatic language first contact with India.

It's interesting to see the first (to my knowledge) PCA chart that includes the Burmese (from my point of view).

I wonder if their cluster analysis suggests that the expanding Burmese (who would be a Tibeto-Burman people presumably akin to the Naxi/Tujia or the median Han Chinese) really did absorb/were absorbed by the Mon/Pyu peoples (presumably akin to the Cambodians) who were their predecessors in Burma and were (which seems like the consensus) or whether this can be attributed to later mixture. The uptick of "light green" component relative to Cambodians suggests some degree of later/other mixture with Indian populations did occur.

I haven’t read the paper and I’m afraid may not be able to do it in the next little while. But I’m not entirely convinced by the paper’s conclusions. Munda is a high-order branch of the AA family. Grammatically, it shows some clear archaisms that are missing from Mon-Khmer. I found the same conservative features in Munda kinship systems, again missing in Mon-Khmer (see The Genius of Kinship, p. 226-227). The Y-DNA genetics of O2a may simply reflect different effective population sizes, with Mon-Khmer being spoken by a population that expanded their pool of reproductively active males, while Munda by a population that contracted it, maybe in response to demographic pressures from Dravidian and Indo-Aryan groups. As far as EDAR is concerned, it codes for not just thick hair but also shovel-shaped incisors and the latter is an archaic trait frequent in neanderthals and Asian Homo erectus that, in modern human populations, shows a pattern of decreasing frequencies from east to west (Europe and Africa). The fact that EDAR is detected in Munda makes me think that it’s older than usually portrayed (African, Australian and European populations independently lost it under selection?) and represents the early east-to-west migration from East Asia into India and West Asia carrying mtDNA M, N and R lineages and Y-DNA DE, P*, F and C lineages. Could we consider a higher-order Y-DNA C5 lineage as the founding Austroasiatic Y-DNA lineage (now found in the speakers of some Khasian languages in Northeast India such as Nongtrai), with O2a evolving later and then migrating (back) to (South)East Asia? Comp. also mtDNA B6 in Khasi (with some strange 9bp deletion cases on the M background in Mundari) dated to some 50K and shared with broader East Asians but not with Mon-Khmer speaking Nicobarese who have B5 (Asian and Non-Asian Origins of Mon-Khmer- and Mundari-Speaking Austro-Asiatic Populations of India, by Kumar, 2006).

I tend to go by linguistic groupings and trait clusters over genetic inferences, when they conflict, and then look for a genetic pattern that supports linguistics, as genetic markers are subject to gene flow, drift, etc. We have good cases studies such as Hungarian, Ket, Burishaski and European Roma that show that gene flow obfuscates ancient kinship or creates illusions of recent common origin, while languages still preserve the former better. O2a may just be an artifact of eff population size differences but otherwise Austroasiatic-speakers expanded from NE India back to (South)east Asia.

"Austro-asiatic languages does not even have remote relationship with Chinese".

That's contradicts what who-ever is responsible for this at Wikipedia thinks:

http://en.wikipedia.org/wiki/Haplogroup_O_(Y-DNA)

The diagram at the bottom of the page attempts to connect O Y-haplogroups with various languages. It separates the languages and haplogroups into northern (Y-DNA O3 and Sino-Tibetan/Hmong-Mien) and southern (Y-haps O1 and O2 and Austric). Included in Austric are Munda/Mon-Kmer, Austronesian and Tai-Kadai.

To consider Y-hap O2 as southern is stretching things. O2b is pretty much northern, and O2a is southern. It is most parsimonious to accept that they separated into the two divisions somewhere near where the two meet up. And O1 is almost certainly an immigrant to Taiwan from somewhere on the mainland. And almost certainly has Chinese Neolithic connections.

This Wiki link:

http://en.wikipedia.org/wiki/Haplogroup_O3_(Y-DNA)

claims:

"Haplogroup O3 is a descendant haplogroup of haplogroup O. Some researchers believe that it first appeared in China approximately 10,000 years ago".

So if the above-mentioned diagram is anything like realistic Sino-Tibetan and Hmong-Mien can only have separated more recently than that. Suspiciously close to the origin of the Chinese Neolithic.

The main article Dienekes has put up also claims that the most likely hypothesis as to the origin of the Indian Austroasiatic-speaking population is:

"The first of these places the origin of Austroasiatic speakers in Southeast Asia with a later dispersal to South Asia during the Neolithic"

Seems that the authors see a strong correlation between the Indian Austroasiatic-speaking people and the SE Asian Neolithic. And other research suggests, in turn, a strong correlation between the SE Asian Neolithic and the Yangtze Neolithic.

This is no evidence of East Asian migration into India, but is simply a reflection of clinalnature of all such DNAs. Moreover, it must be remembered that that O3 and O3a5 originated at the eastern tip of Northeast India, and O3a originated inMyanmar adjoining India, not in China, as has been made clear by study ofHong Shiet al

They have not given data for O3a3,but that must also have originated in between northeast India and Myanmar. Hence finding of merely 5% frequency of EDAR 1540C gene in the IndianAustro-Asiatic speakers should not have warranted the conclusion that thisgene came to India with these people migrating into India with O2a-M95lineage from Southeast Asia. The article also reflects obvious bias and manipulation of data. The authors have not included any Indo-European O2a or Dravidian speaking O2a samplefrom India deliberately. On the other hand in case of Southeast Asia, theyhave included O2a samples from Mainland Southeast Asia, China, Taiwan and Island Southeast Asia. These samples have included individuals speaking notonly Austro-Asiatic languages, but also Daic, Chinese and Austronesianlanguages. This has increased the variability and hence age of the so calledSoutheast Asian sample. Again, the authors have divided Indian Austro-Asiatic speaking O2apopulation in three groups: South Munda, North Munda and Khasi, and theirages have been calculated separately.

But in case of Southeast Asia, theyhave calculated age of “Overall Southeast Asia” which includes Chinese andTaiwanese samples too.

Again, within this group, they have calculated age ofO2a in Mainland SEA and Island SEA. Mainland SEA sample included theChinese sample, and ISEA sample included the Taiwanese samples of Chineselanguage speakers.

Had Dravidian and Indo-European speakers’ O2a beenalso included in the study, and all the Indian samples been consideredtogether, the age of Indian O2a must have far exceeded the overall age of so-called overall SEA age for this haplogroup.

Moreover, the dates arrived at for migration into India (18,600 years back) is too early to be associated with farming if we should believe Bellwood. Thus a reader of this article may get misled by the conclusions of this article,which is no more than personal preferred belief of some of the most powerful authors in this field of human migration.

"it must be remembered that that O3 and O3a5 originated at the eastern tip of Northeast India"

Are you sure about that? O as a whole derives from MNOPS via NO. Of the derived MNOPS haplogroups two are confined to New Guinea and Melanesia (M and S) suggesting that MNOPS diversified somewhere near Wallacea, not in Northeast India. And N is very much a north Chinese haplogroup suggesting that NO diversified somewhere at least as far north as Central China.

"theyhave included O2a samples from Mainland Southeast Asia, China, Taiwan and Island Southeast Asia. These samples have included individuals speaking notonly Austro-Asiatic languages, but also Daic, Chinese and Austronesianlanguages".

We must accept that although a language expansion may be originally associated with some specific haplogroup(s) they are by no means consistently related after the passing of time.

RE: "If so, it undermines Witzel's hypothesis that Austroasiatic is related linguistically to Harappan, which was present thousands of years earlier and is remote from Austro-Asiatic language first contact with India."

People (including some linguists!) do not seem able to read:

I never wrote that (one of) the Harappan language(s) in the Greater Panjab was a Munda language.

The 300-odd word substrate in the oldest Indo-Aryan text, the Rgveda (c. 1200-1000 BCE) has SOME Austroasiatic features but not all, for example hardly any n-infixes. That's why I called it Para-Munda. Which is not = Munda.

Basically, we still don't know and we can call the substrate anything, say Harappan, Para-Harappan or Language Z. (X is taken already, for the Hindi etc.subsrate)

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